Apparatus for manufacturing condenser electrodes



W. L. L. VIVIE June 4, 1940.

APPARATUS FOR MANUFACTURING CONDENSER ELECTRODES Filed March 17, 1938 wm F Z om 5 m0 T M A a HY MB W 5 Patented June4,1940 I 3 I y ments, toRadio Corporation of America, New York, N. Y., a corporation of DelawareApplication March 17, 1938, Serial No. 196,320

In Germany March 30, 1937 3 Claims. (01. 153-64) The invention relatesto a device for manufacthe outside of these recesses. This isparticularly turing condenser electrodes, more particularly forimportant for it is thus possible to make the slidable condensers. widthof the recesses larger than the thickness In the construction of radioreceiving appaof the metal strips-4 or 4' that are utilized so 5 ratus,measuring apparatus and the like there is that without any trouble thestrips may be in- 6 a tendency of reducing the volume as much as sertedor removed. The metal strips 4 and 4' possible. To that end attempts aremade, inter are pressed against the edge of the. strip 2 of the alia toreduce as much as possible, the usual matrix. If the depth of therecesses is chosen dimensions of rotary plate condensers which may 80 asto be smaller than the width of the strips 4 l be achieved in the firstplace by reducing the and 4', the pp edges of the Strips protrude 10distance between the separate plates. from the matrix owing to which itis possible to A distance of 0.5 mm. between the plates or a place aflat base plate 5, with the interposition of rotary condenser entailsdifiiculties in the manua soldering foil 6, on the edges of the stripsand to facture, which difllculties increase with any solder it thereto.

further reduction. Besidesa limit is set to the The sleeve 9 and he se pe 5 r cen er 15 reduction of the dimensions of rotary condensers by ashaft 1 which is slidably arranged in the since for reasons of rigidityit is impossible to sleeve 3. Exact centering is necessary in Order makethe thickness of the separate plates mato ensure t wh n th e c des resubs terially smaller than 0.5 mm, quently assembled to form acondensenthe sleeve l) Slidable condensers having cylindrical or spiral9 may be ut for the mounting as Well as 80 electrodes are materiallybetter from this point for t e guiding during dius m e Shaft 1 of view.The advantages of such condensers as a colla 8 y means of Which theeempleted have been recognized already but the manufacelectrode isexpelled from the matrix. The two j 'sT 'rss ATEN OFFICE ture entailsdifliculties, in particular the mountelectrodes which are formed in thismatrix are asa ing and the exact maintaining of the distance sembled toform a condenser and owing to the 35 between the electrodes. fact thatthe two electrodes are produced with It has previously been proposed toprovide the the ai of the sa matrix a great precision i cylindrical orspiral electrodes, for th mounting the manufacture may be obtained(tolerance less thereof, with a rim and then to secure the latter haeady t a S ht hickness of 80 to a disc-shaped plate. the strips (0.1mm.) a sufiicient rigidity and sta- It has previously further beenproposed to set ty may be ensured in the case of an air g the electrodesin grooved disc-shaped plat of 0.2 mm. If the separate condensers are tobe With these known means it is, however, not assembled to form a u p ndser, it s possible to manufacture condenser electrodes with va ageous tomanufacture all the electrodes suflicient precision. with the aid of thesame matrix. With the meth- 35 According to the invention, a resilientmetal 0d according to the invention it is possible to strip is placed ina matrix which has recesses manufacture Without y diffieulty o d nse sOf which are parallel to the axis of the matrix and very smalldimensions which occupy less than which are adapted to the electrodeshape aimed half he r m taken p by r ry r ry plate 0 at and then an edgeof the metal strip is secured condensers. It is obvious from the abovethat to a further constructive part. by the use of the double endedmatrix the two Figures 1 and 2, which show two cross-secformed condensersections are enantiomorphic in tional views, illustrates the manufactureof a t While t y a Similar y are not p spiral electrode, use being madeof a double matn blerix. The latter consists of a metal strip l which Iclaim: is wound, jointly with a narrower metal strip 2, 1. A matrixadapted to be used in forming on a sleeve 3 and which is kept togetherby a sp r ser plates said matrix being P clamping device not shown).There is thus vided with two oppositely spiral grooves said produced adouble matrix which has two spiral gro ves being arr n o r ve r i ienmetal recesses and the two halves of which have exactstrips and formtherefrom a pair of enantiomor- 50 ly the same dimensions. phic membersadapted to cooperate with each Resilient metal strips 4 and 4', whichform other and form the plates of a condenser. afterwards the electrodesof the condenser, are 2. A matrix adapted to be used in forming insertedinto the spiral recesses of the matrix spiral condenser plates, saidmatrixcomprising and, owing to the bending stresses, they engage a blocklike element provided with a central 55 opening along its axis. a pairoi enantlomorphic spiral grooves formed in said matrix on opposite sidesthereof and so that the axis of the spiral grooves is common with theaxis of said central opening.

3. A matrix adapted to be used in forming spiral condenser plates, saidmatrix comprising a block like element provided with a central openingalong the axis of the block, a spiral recess formed in said block andhaving the same axis as said central opening, said spiral recess beingparallel to said axis and arranged so as to receive a resilient metalstrip which is to be formed into a spiral condenser plate, the depth ofsaid spiral recess being less than thewldth of the strip whereby whenthe strip is inserted in said recess one edge of the strip protrudes anappreciable amount from the block, a centering shaft positioned withinsaid central opening and arranged to receive and fix the position of acon denser plate sleeve member within the central opening, said sleevemember carrying a holding plate which is adapted to be attached to theprotruding edge of the strip whereby withdrawal of the sleeve memberfrom the shaft carries with it the formed spiral condenser plate.

' WILHELMUS LAMBERTUS LEONARDUS VIVIE.

